A continuing demand exists for simple, highly efficient and inexpensive gas compressors as may be useful in a wide variety of gas compression applications. This is because many gas compression applications could substantially benefit from incorporating a compressor that offers a significant efficiency improvement over currently utilized designs. In view of increased energy costs, particularly for both for electricity and for natural gas, it would be desirable to attain significant cost reduction in gas compression. Importantly, it would be quite advantageous to provide a novel compressor which provided improvements (1) with respect to operating energy costs, (2) with respect to reduced first cost for the equipment, and (3) with respect to reduced maintenance costs. Fundamentally, particularly from the point of view of reducing long term energy costs, this would be most effectively accomplished by attaining gas compression at a higher overall cycle efficiency than is currently known or practiced industrially. Thus, the important advantages of a new gas compressor design providing the desirable features of improved efficiency, particularly at part load operation, can be readily appreciated.